The invention relates to a charging device for a motor vehicle with a high-voltage battery, wherein the charging device is designed optionally to charge or to discharge the high-voltage battery, and comprises a supply unit, which is designed to supply a transmission voltage, and a connecting apparatus, which is designed to connect the supply unit to the motor vehicle in order to optionally charge or to discharge the high-voltage battery. The invention further relates to a motor vehicle, a charging arrangement, and a method for operating the charging arrangement.
At present, there are numerous charging standards for cabled AC and DC charging:                combined charging system CCS1 (Europe), CCS2 (NAR) (AC and DC charging)        Chademo (only DC charging)        China GB/T (AC and DC charging)        type 1 AC charging (AC plug for NAR and Japan)        type 2 AC charging (AC plug for Europe)        
Furthermore, work is in progress on the standardization of cableless charging for automated charging. Alternative cabled automated charging systems are not gaining acceptance based on the contact danger and the plugging complexity. Besides safety and complexity, ideas such as the use of plugging robots, for example, are very complicated and therefore expensive.
In the field of utility vehicles, research is in progress on roof systems, for example, which are comparable to the current collectors of trains. On account of the high positioning of said roof systems, the danger posed to a standing user coming into contact with the pole declines.
A charging device mentioned in the introduction is known, for instance, from EP 2 236 344 A2. The charging device is designed in such a way that, in the case of the charging method for a vehicle, a handshake process is carried out after a charging plug has been plugged in. For the protection of an operator, the high charging voltage is applied only after a successful handshake.
Described in DE 11 2011 105 236 T5 is a vehicle that comprises a charging port which is supplied exclusively with low voltage (100 VAC).
A similar idea is known from US 2012/0 055 724 A1. The vehicle comprises a plurality of charging terminals, at least one of which is provided for a charging with low voltage (100 VAC or 200 VAC).
The systems described above are cabled charging systems and necessitate a plugging operation for the charging. These ideas in regard to cabled automated charging systems in the field of automobiles are critical to safety and/or are very complex. Wireless automated charging systems (for example, inductive systems) correspond to the current trend of automobile development. However, these systems are also complex and expensive. At present, a standardization of an automated charging system seems to be in sight solely for inductive charging (public or private charging). In addition to the known cabled and cableless systems, there is accordingly a need for an improved alternative, which offers more comfort, is less expensive, and is more efficient.